1. The problem statement, all variables and given/known data The stream function of a 2D incompressible flow is given by: [tex]\Psi[/tex]=([tex]\Gamma[/tex]/2pi)*ln(r) Show that the circulation about a closed path about the origin is [tex]\Gamma[/tex] and is independent of r. 2. Relevant equations [tex]\Gamma[/tex]=-[tex]\oint[/tex]V dot ds 3. The attempt at a solution So far I know that the radial velocity component Ur=(1/r)*d(Psi)/d(theta)=0 because Psi does not depend on theta. This means that the angular velocity component is the only velocity component: Utheta=-d(Psi)/d(r)=-L/2pi(r) After this point im not exactly sure what to do.